The present invention relates to a process for producing a deformed image without significant image degradation.
Deformable materials with colour and/or black and white motives, particularly those made of plastic, are used e.g. as protective and/or decorative foils particularly in the furniture industry, in which they are used as design elements to cover low-priced and/or light weight carrier materials and/or carrier materials that are critical to the conditions of their use; the configuration of deformable material and carrier material replacing much more expensive and/or heavier and/or less easier to handle and/or less resistant materials such as real wood, stainless steel or marble.
The manufacture of deformed plastic pieces with any kind of representations like images, designs, patterns, letters and so forth, usually proceeds by printing on an undeformed flat foil of a thermoplastic polymer and is then deformed using heat and pressure.
The results obtained are unsatisfactory, because the printed pieces after deformation exhibit a loss in image quality, that is visible at all parts where the deformation has led to an elongation of the deformed material. In particular a significant loss in image quality is observed after deformation at curved parts and still more so at sharp edges, which is particularly noticeable as a bright line and/or increased granularity following the curves and/or edges in homogeneously coloured dark areas, which is unacceptable, particularly in the case of decorated furniture. Furthermore, the printing processes require complicated prepress steps and are therefore expensive and are not suitable for the manufacture of individual designs with small production runs.
Photographic layers, which were laminated onto a support, have, for example, been disclosed in EP-A 0 250 657, U.S. Pat. No. 3,871,119, EP-A 0 490 416 and EP-A 0 276 506 for the manufacture of materials for identity cards and in EP-A 1 189 108 have been disclosed for materials with a broader colour gamut. The layers can subsequently be covered with a protective foil, as disclosed, for example, in U.S. Pat. No. 4,370,397 and GB 2,121,812.
The disclosed ID-cards are all flat, so that there are no requirements regarding deformability and their suitability or otherwise therefor was not disclosed.
Furthermore, as laminatable photographic layers those with special binders have been disclosed, although neither of these options produces an optimum image quality. In particular the graininess realized with state of the art laminatable materials is unacceptably high. The DTR materials that are also known to be laminatable, are not suitable for the furniture industry,because the two-sheet process has not been adapted to the large format automated processing needed in this field.
Representations like images, designs, patterns, letters and so forth, of the highest quality can be realized with colour photographic materials, comprising on a support at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler. As a support for reflective material, paper coated on both sides with polyethylene and for transparent materials longitudinally and laterally stretched polyester is usually used. The deformation according to the present invention of such colour photographic materials is not possible.
The deformability of special photographic materials consisting of a support, an optional adhesive layer and a black and white silver halide emulsion photographic layer with special binders was disclosed in FR 968 638 and GB 739,477. According to FR 968 638 gelatin cannot be used as a binder, because cracking occurred upon bending.
The known deformable photographic materials as disclosed in FR 968 638 and GB 739 477 did not fulfil the present quality requirements for photographically produced images and the bending behaviour was unsatisfactory.
GB 2,321,977 and the corresponding WO98/35269 disclose a mouldable photographic material comprising a thermoplastic base sheet, a primer layer providing a key for a light sensitive layer, and a protective thermoplastic foil, the foil being bonded to the light sensitive layer with an optical quality adhesive.
Furthermore, no deformable photographic materials are known, which are satisfactory for both a long exposure and for a digital exposure, such as, for example, required in the furniture industry, to enable the exposure of large formats. Analogue long exposures are desirable so that inexpensive exposure configurations can be used, but digital exposure is being increasingly required, because it is much faster and because rolls of film are much easier to expose continuously. Furthermore, different designs can be much more easily realized in production, since no film is necessary as an intermediate step. Nowadays new designs are usually produced by computer and can be directly used in digital exposure to realize optimal image quality.
Digital exposure, also known as scanning exposure, proceeds pixel-wise, line-wise or area-wise with high intensity strongly focussed beam of light beam e.g. from lasers, light emitting diodes (LED), DMD (digital micromirror devices) apparatuses, cathode ray tubes and such like and with short to very short exposure times per pixel. A pixel is the smallest image area on the copying material, which can be addressed by the exposure apparatus. Conventional silver halide emulsions exhibit a too low sensitivity, due to an unsatisfactory reciprocity, which results in a too low contrast and insufficient maximum density at such short exposure times.
A similar reciprocity failure is also observed at exposure times above 10 s (long exposure times), which are necessary for analogue exposure of large formats.
It is therefore an object of the present invention to provide a process for producing deformed colour photographic materials, which enables high quality representations such as images, designs, patterns, letters and so forth to be realized, which undergo the desired deformation by heat and/or pressure without significant visible loss in image quality. A further advantage of the present invention compared to printing processes is the possibility to produce even single pieces as a proof or demonstration example.
Further aspects and advantages of the invention will become apparent from the description hereinafter.
It has been surprisingly found that the deformable colour photographic recording materials used in the process of the present invention are suitable for digital exposure and give high quality images.
Surprisingly it has been found, at variance with the disclosure in FR 968 638, that gelatin can be successfully used in the materials used in the process according to the present invention. The reason why the use of gelatin failed according to FR 968 638, but surprisingly was very successful for the present invention, may be the difference between single layer black and white materials like those described in FR 968 638, that essentially only contain silver halide crystals dispersed in the binder, and multilayer colour photographic materials according to the present invention, that also comprise softer materials like couplers in their layers.
According to the present invention, a process is provided for producing a deformed image comprising the steps of: digitally exposing a colour photographic silver halide material, said colour photographic silver halide material comprising on a deformable plastic support at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler; conventionally processing said exposed colour photographic material to produce an image; and deforming said colour photographic material.